Question

Identify the following elements: (a) A member of the same period as tellurium with two fewer protons than tellurium. (b) A transition metal in Group 5, period 4. (c) An alkali with 55 protons. (d) A metalloid in Group 15 with more than 40 protons.

Short answer

Question: Identify the elements based on the given conditions: (a) A member of the same period as tellurium with two fewer protons than tellurium (b) A transition metal in Group 5, period 4 (c) An alkali with 55 protons (d) A metalloid in Group 15 with more than 40 protons Answer: (a) Tin (Sn) (b) Vanadium (V) (c) Cesium (Cs) (d) Antimony (Sb)

Step-by-step solution

(a) A member of the same period as tellurium with two fewer protons than tellurium

Tellurium (Te) is in period 5 and has 52 protons. To identify an element with two fewer protons, we need to subtract two from the atomic number of Tellurium. 52 - 2 = 50 Now, we look for the element with 50 protons which is Tin (Sn). Tin is also in period 5, so it meets the required condition.

(b) A transition metal in Group 5, period 4

Transition metals are the elements found in groups 3-12 of the periodic table. We are looking for a transition metal in Group 5 and period 4. The element that meets this condition is Vanadium (V).

(c) An alkali with 55 protons

Alkali metals are the elements found in Group 1 of the periodic table. We need to find an alkali metal with 55 protons. The element with 55 protons is Cesium (Cs), which is an alkali metal and belongs to Group 1.

(d) A metalloid in Group 15 with more than 40 protons

Metalloids are the elements that have properties of both metals and non-metals. They are found along the staircase line in the periodic table between the metals and non-metals. We are looking for a metalloid in Group 15 with more than 40 protons. The metalloid in Group 15 is Antimony (Sb) with 51 protons, which fulfills the condition of having more than 40 protons.

Key concepts

Transition Metals

Transition metals are a class of elements characterized by their position on the periodic table. They occupy the central block of the table, specifically groups 3 through 12. These metals are known for their ability to form colorful compounds, and they are often used as catalysts in chemical reactions due to their ability to adopt a variety of oxidation states.

Some common examples of transition metals include iron (Fe), copper (Cu), and gold (Au). When identifying a transition metal like Vanadium (V), noted in the exercise, it’s important to remember these elements' defining characteristics, such as their d-block orbital filling and typical metallic properties such as high melting points, malleability, and electrical conductivity.

Alkali Metals

Alkali metals reside in Group 1 of the periodic table and are best known for being highly reactive, particularly with water. These elements include Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr). They all have one electron in their outermost shell, which makes them very eager to lose that electron in chemical reactions, resulting in a +1 oxidation state.

The identification of Cesium (Cs) as the alkali metal with 55 protons illustrates the process of using the atomic number to identify an element. Alkali metals have a low density, and many can float on water, and they also have low melting points relative to other metals.

Metalloids

Metalloids possess properties of both metals and non-metals, placing them on the borderline of the two categories. They are found adjacent to the staircase line that distinguishes metals from non-metals on the periodic table. Examples include Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), and Tellurium (Te).

Metalloids are versatile in their applications, often used in semiconductors and other electronic devices. As noted in the exercise, Antimony (Sb) is the metalloid in Group 15 with 51 protons, exhibiting mixed properties such as semi-conductivity and variable oxidation states that make them unique.

Atomic Number

The atomic number is a fundamental characteristic of an element, representing the number of protons in an atom's nucleus. It is the defining attribute that determines the identity of the element. Each element on the periodic table has a unique atomic number; for example, Hydrogen has an atomic number of 1, which means it has one proton in its nucleus, while Carbon has an atomic number of 6 with six protons.

In the exercise, atomic numbers allow for the identification of elements by their proton count. For instance, tellurium, with an atomic number of 52, helps us to find tin (Sn), which has an atomic number of 50. Understanding the atomic number is essential not only for identifying elements but also for predicting their chemical properties since the number of protons affects the structure of the electron shells and thus, the reactivity of the atom.